Why does my Audi A3 produce black smoke from the exhaust?

I recently noticed that my Audi A3 has been producing black smoke from the exhaust. It is not consistent, but it seems to happen more frequently when I am accelerating. Can someone explain to me what could be causing this issue and if it needs to be addressed?

Black smoke from the exhaust is typically a sign of an overly rich fuel mixture, meaning there is too much fuel being injected into the engine. This can be caused by a number of factors, including a faulty oxygen sensor or a clogged air filter. It is important to have this issue addressed promptly, as it can lead to decreased fuel efficiency and potential damage to the catalytic converter.